DE112019001298T5 - Display device - Google Patents

Abstract

The invention provides a display device which enables ideal image display with a simple device structure. The display device comprises a screen for displaying an image based on a plurality of image patterns, a plurality of light sources for illuminating the screen divided into a plurality of areas, each area being individually backlit, a storage part for storing luminance information in which each Image pattern is associated with a luminance of each of the light sources in the image pattern, and a luminance control part for controlling the luminance of each of the light sources based on the luminance information. The luminance control part gradually changes the luminances of the light sources from before luminances of the light sources to after luminances of the light sources.

Description

Technical area

The invention relates to a display device.

Technical background

Liquid crystal displays for displaying images are conventionally known, as is a technique of controlling a backlight with a plurality of light sources illuminating a liquid crystal display from the back, the surface of the liquid crystal display being divided into a plurality of display areas, a maximum luminance value (peak brightness value) for pixels in each of the display areas is detected and, based on these peak brightness values, the brightness of the background lighting is controlled for each display area (local dimming control) (cf. patent document 1).

Prior art document

Patent document

Patent Document 1: JP 2007-279395 A

Summary of the invention

Object to be solved by the invention

The above local dimming control is effective in that the dynamic range can be maintained. However, processing is required here to detect the peak brightness value for each display area every time based on image signals relating to the obtained image. Therefore, an algorithm specifically for detecting peak brightness values is required, and it is necessary to provide an integrated circuit specifically for local dimming control. This complicates the processing system of the apparatus as a whole and increases the cost of production.

The present invention has been made in view of the above and aims to provide a display device which enables ideal image display with a simple device structure.

Means for solving the task

To achieve the above object, the display device according to the present invention comprises a screen for displaying an image based on a plurality of image patterns, a plurality of light sources for illuminating the screen divided into a plurality of areas, each area being individually backlit Storage part for storing luminance information in which each image pattern is associated with a luminance of each of the light sources in the image pattern, and a luminance control part for controlling the luminance of each of the light sources based on the luminance information.

Advantages of the invention

In the display device of the present invention, an ideal image display is enabled with a simple device structure.

Figure list

• 1 Fig. 3 is a front view of a display device according to an embodiment of the present invention.
• 2 Fig. 13 is a simplified functional block diagram of a functional structure of the display device.
• 3 Fig. 13 is a simplified explanatory diagram of a light source substrate having a screen and a backlight unit.
• 4 (a) Fig. 13 is an explanatory view of an exemplary first image pattern, and 4 (b) Fig. 13 is an explanatory diagram abstractly showing luminance information corresponding to the first image pattern.
• 5 (a) Fig. 13 is an explanatory view of an exemplary second image pattern, and 5 (b) Fig. 13 is an explanatory diagram abstractly showing luminance information corresponding to the second image pattern.
• 6 (a) Fig. 13 is an explanatory view of an exemplary third image pattern, and 6 (b) Fig. 13 is an explanatory diagram abstractly showing luminance information corresponding to the third image pattern.
• 7th Fig. 13 is a sequence diagram for explaining luminance control processing performed by the display device according to the present embodiment.
• 8th FIG. 13 is a graph showing the luminance control processing in FIG 7th illustrated.
• 9 Fig. 14 is a sequence diagram for explaining another luminance control processing performed by the display device according to the present embodiment.
• 10 FIG. 13 is a graph showing the luminance control processing in FIG 9 illustrated.
• 11 (a) Fig. 13 is a table showing the relationship between a degree of transparency of the screen and an LED luminance based on a comparative example. 11 (b) Fig. 13 is a table showing the relationship between a degree of transparency of the screen and an LED luminance in a display device according to the present embodiment. 11 (c) is a graph showing the relationship between the in 11 (a) luminance shown of a screen of a display device according to the present embodiment and the in FIG 11 (b) shows luminance of a screen of the comparative example shown.

Embodiment of the invention

An embodiment of the display device according to the invention will now be explained with reference to the accompanying drawings. The display device according to the invention can be applied to all display devices which have a screen with backlighting and is mounted, for example, in vehicles such as automobiles and motorcycles, in ships, agricultural implements and construction machines. In the present embodiment, the present invention will be explained using an example in which a display device according to the invention is mounted in a car and the display device comprises a liquid crystal display.

1 Fig. 3 is a front view of a display device 1 according to an embodiment of the present invention.

2 Fig. 13 is a simplified functional block diagram of a functional structure of the display device 1 .

3 Fig. 13 is a simplified explanatory diagram of a light source substrate 31 with a screen 11 and a backlight unit 12th . 3 (a) is a front view, and 3 (b) is a sectional view along the line BB.

In the following explanation, “front” refers to the side facing the reader in 1 and the top in 3 (the screen 11 facing side) and means the side perceived by the viewer (driver). "Back" means the back in 1 and the lower side (the light source substrate 31 facing side) in 3 .

Main components of the display device 1 are a housing 10 , a screen 11 , a backlight unit 12th and a circuit board 13th .

The case 10 takes the screen 11 who have favourited the backlight unit 12th and the circuit board 13th inside. The case 10 forms the exterior of the display device 1 .

The screen 11 is a TFT (Thin Film Transistor) type liquid crystal display. The screen 11 consists of a pair of front glass substrates in which a liquid crystal layer is enclosed. Transparent electrodes are formed on the pair of glass substrates by ITO (Indium Tin Oxide), etc. The screen 11 further comprises a pair of polarizing front disks (polarizing filters) which are arranged such that the pair of front glass substrates are pinched. The screen 11 is connected to the circuit board via an FPC (Flexible Printed Circuits) 13th connected. The screen 11 is from the control part 50 the circuit board 13th controlled so that a drive voltage is applied to the liquid crystal layer through the transparent electrodes. This controls the orientation of liquid crystal molecules in the liquid crystal layer and thus the degree of transparency of individual pixels 21st on the screen 11 changed. Through a combination of such pixels 21st the screen shows 11 displays an image based on a plurality of image patterns (explained below) stored in advance.

The backlight unit 12th is behind the screen 11 arranged. The backlight unit 12th consists of a light source substrate 31 and a (not shown) light guide and illuminates the screen 11 from behind. On the light source substrate 31 A plurality of LEDs (Light Emitting Diode) 32 which are an example of light sources are attached. The light source substrate 31 is via a flexible circuit board, e.g. B. an FPC, with the circuit board 13th connected. When the LEDs 32 a drive current is supplied, give them to the screen 11 (Light guide body) light out. The light guide conducts this from the LEDs 32 emitted light towards the screen 11 . The light guide is a flat, transparent resin, such as polymethyl methacrylate (PMMA) or the like.

As in 3 shown, each LED illuminates 32 one area each 40 on which in a variety of areas 40 split screen 11 from behind. Each of the areas 40 comprises a large number of pixels 21st (in 3 e.g. 4x4 pixels). Therefore a single LED illuminates 32 the multitude of pixels 21st that are in the area 40 are included. In other words, the area is 40 a lighting area of a single LED 32 and this illumination area comprises a plurality of pixels 21st .

Main component of the circuit board 13th is a control part 50 to control the screen 11 and the backlight unit 12th .

The control part 50 is equipped with a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and, for example, performs certain calculation processing according to a program written in the ROM. The control part 50 receives from the vehicle ECU (Electronic Control Unit), for example, a vehicle speed, an engine speed, various vehicle information, navigation information, etc. through various kinds of sensors. Based on the information received, the control part initiates 50 the screen 11 To display information.

The control part 50 is with a pattern selection part 51 , a memory part 52 , a screen control part 53 and an LED control part 54 fitted.

The pattern selection part 51 selects for example based on information its display on the screen 11 based on information received from the ECU, the required image pattern has been selected from a plurality of image patterns (explained below). The pattern selection part 51 reads luminance information from the storage part based on the selected image pattern 52 out. The pattern selection part 51 controls the screen control part based on the luminance information 53 and the LED control part 54 .

The memory part 52 stores luminance information in which each image pattern corresponds to the luminance of each LED 32 is associated in the image pattern (explained below).

The screen control part 53 is a so-called GDC (Graphics Display Controller), generated based on commands from the pattern selection part 51 etc. a required picture and shows the picture on the screen 11 at. The screen control part 53 (Transparency degree control part) controls a transparency degree of each of the pixels 21st especially by controlling the drive voltage of the liquid crystal layer.

The LED control unit 54 (Luminance control part) controls based on commands from the pattern selection part 51 etc., that is, based on the luminance information, the luminance of each of the LEDs 32 .

Now, in the event that, as in the display device 1 according to the present embodiment, a plurality of LEDs 32 are present that each area 40 one in a variety of areas 40 split screen 11 backlighting, using a local dimming control. Local dimming control is used on TVs, etc., and controls the luminance for each area 40 individually, each of one of the LEDs 32 corresponds. However, there will be one for built-in processings for the screen 11 and the LEDs 32 Serving integrated circuit and a special algorithm are required in order to adequately execute a local dimming control. The integrated circuit calculates based on, for example, the control part 50 received commands for image display the optimal luminance of the LEDs 32 and executes processing to correct appropriate image information upon image formation. Use of this integrated circuit leads to complication of the processing system of the display device 1 as a whole, as well as an increase in production costs.

On the other hand, in a display device 1 for use in a motor vehicle as compared to a television, etc., display contents (images) are restricted so that the display contents can to a certain extent be grouped into patterns. The display device is used for this 1 according to the present embodiment designed so that the luminances of the LEDs 32 every area 40 , which correspond to an image pattern, are stored as luminance information and, by reading them in, the LEDs 32 being controlled. Therefore, there is no correction processing with regard to the luminance of the LEDs that is accompanied by an image change 32 and performed on image formation or the like. This requires the display device 1 no integrated circuit, algorithm, etc. specifically for the local dimming control, which can simplify the device structure and mitigate the increase in production cost. Processing for luminance control of the display device will now be described below 1 of the present embodiment explained in detail.

The 4 (a) , 5 (a) and 6 (a) are explanatory illustrations of exemplary image patterns.

A first to third pattern are prepared as image patterns, for example, those on the screen 11 displayed content are divided.

The first image pattern comprises, as in 4 (a) shown, images left and right on the screen 11 who have favourited a speedometer 61 and an engine tachometer 62 represent. The first image pattern also includes between the speedometer 61 and the engine tachometer 62 a picture of a vehicle 63 driving in front of your own vehicle, an odometer 64 and turn signals 65 indicating a right or left turn.

The second image pattern comprises, as in FIG 5 (a) shown, an image on the left of the screen 11 who have a speedometer 61 represents. The second image pattern also includes on the right side of the screen 11 navigation information 66 (Route guidance), an odometer 64 and turn signals 65 indicating a right or left turn.

The third image pattern comprises, as in 6 (a) shown, images left and right on the screen 11 who have favourited a speedometer 61 and an engine tachometer 62 represent. The third image pattern also includes between the speedometer 61 and the engine tachometer 62 for example a picture that has a warning 67 with respect to a small amount of fuel remaining means an odometer 64 and turn signals 65 indicating a right or left turn.

The 4 (b) , 5 (b) and 6 (b) are explanatory representations that abstractly represent luminance information corresponding to the image patterns.

Luminance information is information in which each image pattern matches the luminance of each of the LEDs 32 is associated in the image pattern. In other words, an area 40a in which no image is displayed (formed) in the first image pattern does not have to be an LED 32 be illuminated, as in 4 (b) shown. That is why the luminance of the LED is 32 set to 0% in area 40a (minimum brightness value: switched off state). On the other hand, for example, an area 40b in which the image of the speedometer 61 is indicated by an LED 32 be illuminated. That is why the luminance of the LED is 32 set to 100% (maximum brightness value) in area 40b. The luminance of the LEDs 32 are also set to values other than 0% and 100%. For example, in a region 40c where the luminance of the image is set lower than that in the region 40b, the luminance of the LED is 32 set to 75%. The luminance is preferably set according to the need for the display content (information) for the driver.

Just like in 4 (b) are also in the 5 (b) and 6 (b) Areas 40 with a low set luminance of the LED 32 with black (filled areas) and areas 40 with luminance set high, shown in white.

Next is one from the control section 50 Executed processing for luminance control of the LEDs 32 explained.

7th Fig. 13 is a sequence diagram for explaining one of the display device 1 luminance control processing performed according to the present embodiment.

8th FIG. 13 is a graph showing the luminance control processing in FIG 7th illustrates, where (a) the relationship between luminance of an image and time and (b) the relationship between luminance of an LED 32 and time illustrates.

In step S1, the pattern selection part receives 51 an instruction to change the picture, which is a change of the on the screen 11 displayed image. In step S2, the pattern selection part selects 51 Based on the instruction to change the image, a suitable image pattern is selected from image patterns stored in advance. When the pattern selection part 51 for example, has received an instruction to display navigation information, it selects that in 5 (a) second image pattern that contains the navigation information 66 indicates.

In step S3, the pattern selection part reads 51 based on the selected image pattern, luminance information from the memory part 52 out. In other words, the pattern selection part 51 receives information about the luminance of the LED 32 that each of the areas 40 illuminate in the selected image pattern. In step S4, the pattern selection part sends 51 the luminance information to the LED control unit 54 . In step S5, the pattern selection part transmits 51 an instruction to change the image and image information which is used to generate an image corresponding to the selected image pattern to the screen control part 53 .

In step S6, the LED control part changes 54 current luminance levels of the LEDs based on the received luminance information 32 to the luminances specified with the luminance information. The LED control unit 54 now changes the luminance of the LEDs 32 stepwise from (current) before-luminance of the LEDs 32 to after-luminance of the LEDs 32 . Therefore, step S6 is the step in which the LED control part 54 a change begins, ie it begins to change the luminances of the LEDs 32 to change after-luminances.

In step S7, the screen control part changes 53 based on the received image information that on the screen 11 displayed image. This step S7 is carried out after the LED control part 54 the change in luminance has started. This is because a changing speed for images is higher than a changing speed for luminances of LEDs 32 . In step S8, the LED control part ends 54 the gradual change in the luminance of the LEDs 32 that is, it includes the change to the one with the luminance information specified luminance levels. The processing for luminance control is based on the 8th explained by way of example.

For example, an image is displayed in which the luminance of a certain area 40 is low (luminance of the LED 32 at 0%). Now the pattern selection part receives 51 an instruction for changing the picture, which allows this picture to be changed to a picture with high luminance (luminance of the LED 32 at 100%) (step S1). The LED control unit 54 changes the luminance stepwise to 100% based on received luminance information (step S4) (steps S6, S8). In the event that t seconds are required from the beginning to the end of the change in luminance, for example, the LED control part increases 54 the luminance 1 / 4t seconds after the start to 25%. The LED control unit 54 then increases the luminance 2 / 4t seconds after the start to 50% and 3 / 4t seconds after the start to 75%. In addition, the screen control part changes 53 the image in the period between the beginning and the end of the change in luminance of the LED 32 (Step S7).

Such processing is carried out, as in 8th is also executed when an image change instruction has been received instructing a change from a high-luminance image to a low-luminance image.

As a result, an image corresponding to the instruction to change the image appears on the screen 11 displayed. In particular in that the display device 1 the luminance of the LEDs 32 changes gradually, images can be displayed without causing discomfort to the driver.

In other words, with such processing for luminance control, the screen receives them 11 controlling screen control part 53 and that the LEDs 32 controlling LED control unit 54 commands from the pattern selection part 51 and control the screen 11 and the LEDs 32 . Therefore, there may be time differences between the picture changes on the screen 11 and the change in luminance of the LEDs 32 come. Such deviations cause discomfort in the viewer. In contrast, the display device leads 1 a gradual change in luminance compared to the change in the image, so that, thanks to a visual effect that gradually makes images appear to be displayed, any discomfort caused by deviations can be reduced.

Thanks to the visual effect that gradually makes images appear, discomfort caused by deviations can be alleviated. On the other hand, there is also the risk that information of great importance, such as warnings or the like, is only perceived by the driver with a delay. Therefore, the display device 1 also perform a different luminance control (with a different luminance change speed) based on an importance of an image.

In other words: the LED control part 54 changes when the first image sample or image is displayed on the screen 11 with the in 7th explained processing for luminance control the luminance of the LEDs 32 step by step of the before-luminance of the LEDs 32 to after-luminance of the LEDs 32 . Also, the LED control part changes 54 when displaying the second image sample or the second image on the screen 11 as below using the 9 explains the luminance of the LEDs 32 directly from the prior luminance levels of the LEDs 32 to after-luminance of the LEDs 32 . This above-mentioned “second image pattern or second image” means information of greater importance than the “first image pattern or first image”. In the following, processing for luminance control corresponding to the importance is explained in detail.

If processing for luminance control corresponding to the importance is carried out, the memory part stores 52 Luminance information in which, taking into account the importance of the image patterns, each image pattern has a mode of changing the luminance of each of the LEDs 32 is associated. The importance can be set individually for each image pattern, but it can also be set for each image (display content) in an image pattern. The luminance information includes, for image patterns or images (image patterns, etc.) with high importance, control information that states that the luminances of the LEDs 32 should not be changed gradually, but immediately. “Change immediately” means that a change occurs at a higher rate than the change in luminance of the LEDs 32 at the in 7th specified processing for luminance control should be performed, it being sufficient that the change is faster relative to a "gradual change". In other words: the display device 1 changes the luminance of the LEDs for normal picture patterns etc. (not very important) 32 step by step and for picture patterns etc. with great importance the luminance of the LEDs 32 faster than for normal image patterns, etc., so that the image change is carried out immediately.

The importance can for example be determined according to an urgency level of the message for the driver. For example, in the in 6th The third image pattern shown is the image representing the warning 67 with respect to a small residual amount of a fuel means having an image (information) with higher importance than the other images in the third image pattern and than the first and second image patterns. In addition to the in 6th shown warning 67 also an image (information) that prompts you to brake, images indicating dangers, etc.

9 Fig. 13 is a sequence diagram for explaining another one of the display device 1 luminance control processing performed according to the present embodiment.

10 FIG. 13 is a graph showing the luminance control processing in FIG 9 illustrates, where (a) the relationship between luminance of an image and time and (b) the relationship between luminance of an LED 32 and time illustrates.

Steps S11 and S12 are identical to steps S1 and S2 in FIG 7th so they will not be explained again here. In step S13, the pattern selection part reads 51 based on the selected image pattern, luminance information from the memory part 52 out. Here, in luminance information for image patterns, etc., control information is included with great importance, which states that the luminances of the LEDs 32 should be changed immediately.

In step S14, the pattern selection part transmits 51 the luminance information to the LED control unit 54 . If the luminance information contains control information that states that the luminance of the LEDs 32 are to be changed immediately, the pattern selection part 51 this on. Step S15 is identical to step S5 in FIG 7th so it is not explained again here. In step S16, the LED control part changes 54 the current luminance of the LEDs based on the received luminance information 32 to the luminances specified with the luminance information. The LED control unit 54 changes the luminance of the LEDs here 32 directly from (current) prior luminance levels of the LEDs 32 to after-luminance of the LEDs 32 . In step S17, the screen control part changes 53 based on received image information that on the screen 11 displayed image. This step S17 is carried out after the LED control part 54 the luminance has changed (completion of the change).
This processing for luminance control is based on the 10 explained by way of example.

For example, an image is displayed in which the luminance of a certain area 40 is low (luminance of the LED 32 at 0%). Now the pattern selection part receives 51 an instruction for changing the picture, which allows this picture to be changed to a picture with high luminance (luminance of the LED 32 at 100%) (step S11). The pattern selection part 51 changes based on the luminance information from the storage part 52 (Step S14) the luminance immediately becomes 100% (Step S16). In addition, the screen control part changes 53 the picture after the luminances of the leds 32 have been changed (step S17).

Such processing is carried out, as in 8th is also executed when an image change instruction has been received instructing a change from a high-luminance image to a low-luminance image.

This allows the display device 1 by immediately displaying image patterns, etc. with high importance, more adequately informing the driver of necessary information according to a level of urgency, etc. than in the case that the in 7th processing for luminance control shown is executed.

With the display device 1 According to the present embodiment described above, ideal image display is enabled with a simple device structure.

However, as in 3 shown, one of an LED 32 illuminated area (area 40 ) a large number of pixels 21st . Therefore, there may be an area 40d that is a boundary of an image 70 includes, pixels 21st with different luminance includes.

11 (a) is a table showing, for example, the relationship between a degree of transparency of the screen 11 and luminance of the LEDs 32 shows based on a comparative example. In 11 "Pixel position" corresponds to a number, the pixels 21st in areas 40e, 40d, 40f in 3 (b) were assigned. Furthermore, the "screen luminance" is a value that results from multiplying the degree of transparency of the screen 11 and the luminance of the LED 32 results.

In 3 (a) the area 40d comprises a border of the image 70 (between the pixel positions 6 and 7). Therefore it can happen that he has pixels 21st with different degrees of transparency, ie, pixels 21st with high luminance (degree of transparency 5%) and pixels 21st with low luminance (degree of transparency 1%). In this case the LEDs choose 32 a luminance with which the image 70 in which the limit of the picture 70 comprehensive area 40d is optimally displayed, and illuminate with this. In concrete terms, an average value is derived from the luminance (20%) of the LED 32 of the area 40e adjacent to the area 40d, which the image 70 does not include, and the luminance (100%) of the LED 32 des to area 40d adjacent area 40f that contains the image 70 includes, as the luminance of the LED 32 set in area 40d, in this case 60%. In other words: an LED 32 illuminates the area 40d which is the boundary of the image 70 using an average luminance from the luminance of the LED 32 of the area 40e composed only of pixels 21st with low luminance, and the luminance of the LED 32 of the area 40f consisting only of pixels 21st with high luminance.

With such control there are differences in the luminance of the screen 11 Noticeable at image borders because the luminance of the LEDs 32 at the boundary between area 40d and area 40f on the screen 11 differ, though the picture 70 is displayed across areas 40d and 40f. Now what the example in 11 (a) concerns, the luminance of the LED lies 32 in the range 40d at 300 and the luminance of the LED 32 in the area 40f is 500, so that there is a luminance difference on the screen 11 occurs.

In order to correct such a luminance difference, the display device is 1 according to the present embodiment arranged so that the degrees of transparency of the pixels 21st which is where the border of the picture 70 encompassing area 40d and areas 40e, 40f adjoining this area 40d encompassing the border of the image, between which the border of the image 70 comprehensive area 40d and the border of the image on these 70 comprehensive area 40d adjacent areas 40e, 40f are gradually changed. This degree of transparency control is carried out by the memory part 52 Transparency level information, which is set so that the transparency levels of the pixels 21st which is where the border of the picture 70 encompassing area 40d and areas 40e, 40f adjoining this area 40d encompassing the border of the image, between which the border of the image 70 comprehensive area 40d and the border of the image on these 70 encompassing area 40d, adjacent areas 40e, 40f are gradually changed, together with the luminance information stored in advance, and the screen control part 53 (Transparency degree control part) the transparency degrees of the pixels 21st based on this transparency level information. In other words: the display device 1 saves to the border of the image 70 related degrees of transparency in advance as degree of transparency information and controls the degree of transparency of the screen by reading this degree of transparency information 11 .

11 (b) is a table showing the relationship between the degree of transparency of the screen 11 and the luminance of the LED 32 at the display device 1 according to the present embodiment. 11 (c) is a graph showing the relationship between the in 11 (a) screen luminance shown 11 the display device 1 according to the present embodiment and the in 11 (b) screen luminance shown 11 of the comparative example shows.

The display device 1 according to the present embodiment is arranged so that the degrees of transparency of the pixels 21st which is where the border of the picture 70 comprehensive area 40d and the area 40f adjoining this area 40d (includes the image 70 ) are gradually changed to 2% to 5% between the area 40d and the area 40f. The display device 1 is also arranged so that the degrees of transparency of the pixels 21st which is where the border of the picture 70 comprehensive area 40d and the area 40e adjoining this area 40d (includes the image 70 not), can be changed gradually to 1% to 4% between the area 40d and the area 40e. In other words, the degree of transparency of the screen 11 on the border of the picture 70 (between the pixel positions 6 and 7) are not changed suddenly, but rather the degrees of transparency of the pixels adjoining the border 21st changed gradually (staggered).

The display device represents 1 also the luminance of the LEDs 32 such that borders are not noticeable. For example, as in 11 (b) shown, together with the luminance of 60% in the area 40d encompassing the boundary, the luminance in area 40f is also reduced (95%) and the luminance in area 40e is increased (25%). Luminance differences compared to the in 11 (a) case shown in which the luminance of the LED 32 in the range 40f to 100% and the luminance of the LED 32 in the range 40e were set to 20%, without including any limits in the consideration, can be mitigated.

Such a degree of transparency control is carried out in that, for example, in step S3 in 7th and in step S13 in 9 the pattern selection part 51 Transparency level information from the storage part 52 reads and in step S5 and step S15 commands to the screen control part 53 granted.

As in 11 (c) shown, the display device 1 by performing such transparency degree control, luminance differences of the screen 11 at the borders of the picture 70 soften and the picture 70 display adequately without noticing the boundaries.

Some embodiments of the present invention have been explained. These embodiments are to be understood and are only as examples not intended to limit the scope of the invention. Various forms of implementation are possible in new embodiments, and various omissions, substitutions and changes may be made as long as they are within a scope that does not depart from the gist of the invention. Such embodiments and changes are within the scope and spirit of the invention, and they are within the equivalent scope of the invention disclosed in the claims.

The screen 11 is not limited to a liquid crystal display, but may be any other backlit screen.

In the 11 (b) The illustrated degree of transparency control can also be performed independently of the processing for luminance control according to FIG 7th and 9 are executed.

List of reference symbols

1

Display device

10

casing

11

screen

12

Backlight unit

13th

Circuit board

21st

Pixel

31

Light source substrate

32

LED (Light Emitting Diode, light source)

40

Area

50

Control part

51

Pattern selection part

52

Storage part

53

Screen control part (transparency degree control part)

54

LED control part (luminance control part)

61

Speedometer

62

Engine tachometer

63

vehicle

64

Odometer

65

indicator

66

Navigation information

67

warning

70

image

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• JP 2007279395 A [0003]

Claims (5)

A display device comprising a screen for displaying an image based on a plurality of image samples, a plurality of light sources for illuminating the screen which is divided into a plurality of areas, each area being individually backlit, a storage part for storing luminance information in which each image pattern is associated with a luminance of each of the light sources in the image pattern, and a luminance control part for controlling the luminance of each of the light sources based on the luminance information. Display device according to Claim 1 wherein the luminance control part gradually changes the luminances of the light sources from before-luminances of the light sources to after-luminances of the light sources. Display device according to Claim 1 wherein the luminance control part changes the luminances of the light sources gradually from before luminances of the light sources to after luminances of the light sources when displaying a first image pattern or a first image on the screen, and when displaying a second image pattern or a second image on the screen changes the luminances of the light sources immediately from before luminances of the light sources to after luminances of the light sources. Display device according to Claim 3 , the second image pattern or the second image being information of greater importance than the first image pattern or the first image. Display device according to Claim 1 , further comprising a degree of transparency control part for controlling a degree of transparency of each pixel on the screen, the areas including a plurality of pixels, the storage part also storing transparency degree information set to be degrees of transparency of the pixels included in an area including a boundary of the image the areas adjoining this area including the boundary of the image between which the area including the boundary of the image and the areas adjoining this area including the boundary of the image are gradually changed, and the transparency degree control part controls the transparency degrees of the pixels based on the transparency degree information.

Images